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Does the plug fit, does it have the correct polarity?
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ZoredacheApr 30 '12 at 17:15

So the question is are you willing to risk releasing the magic smoke. If yes, then plug it in and see.
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ZoredacheApr 30 '12 at 18:15

If you're seriously asking this question I'm going to assume you're asking about a consumer/home router (D-Link. Linksys, Netgear), and not a "real" router (Cisco, Juniper) which typically takes mains voltage directly without a wall-wart. While consumer hardware is not strictly verboten here the best thing we can tell you is "Check the polarity, try it and see, and be aware that you're almost certainly voiding your warranty." -- further questions about this warranty-voiding activity are probably better suited to Super User :-)
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voretaq7♦Apr 30 '12 at 18:55

Technically, it's fine, providing the polarity is correct, it uses the same voltage and has a higher current rating than the device draws.

From a safety perspective, it depends. If the device is protected by fuses, it should be okay, however if it isn't and a fault develops, the device could draw the maximum current the PSU can provide, which could cause a fire if the device isn't rated to handle that level of current.

I wouldn't worry about getting a PSU that is rated slightly higher than the current draw of the device, but if in doubt, hit your local electronics component retailer, who should be able to supply you with the correctly rated PSU.

The difference matters. If you have more supply the demand then things should work. If you have less supply then demand you may release the magic smoke, or see some other failure.
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ZoredacheApr 30 '12 at 18:13

I was only sharing my own experience of the exact same situation.
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Christopher HackettApr 30 '12 at 19:13